Re: [PATCH] staging: comedi: register sysfs device attributes withdriver core

From: Ian Abbott
Date: Fri May 11 2012 - 09:14:06 EST

On 2012-05-11 07:16, Dan Carpenter wrote:
On Thu, May 10, 2012 at 06:05:28PM -0700, H Hartley Sweeten wrote:
-static const struct attribute_group comedi_sysfs_files = {
- .attrs = comedi_attrs,
+static struct device_attribute comedi_dev_attrs[] = {
+ __ATTR(max_read_buffer_kb, S_IRUGO | S_IWUSR,
+ show_max_read_buffer_kb, store_max_read_buffer_kb),
+ __ATTR(read_buffer_kb, S_IRUGO | S_IWUSR | S_IWGRP,
+ show_read_buffer_kb, store_read_buffer_kb),
+ __ATTR(max_write_buffer_kb, S_IRUGO | S_IWUSR,
+ show_max_write_buffer_kb, store_max_write_buffer_kb),
+ __ATTR(write_buffer_kb, S_IRUGO | S_IWUSR | S_IWGRP,
+ show_write_buffer_kb, store_write_buffer_kb),

Some of these are group writable and some are only user writable so
it's not consistent. Probably just make them user writeable.

I guess this was in the original code too, but it's just more
obvious now that they're grouped together.

Is it possible to change (group) ownership of these attribute files using udev rules? Ideally, users in the group that has group ownership on the /dev/comedi* files should be able to modify the read_buffer_kb and write_buffer_kb attribute files as well, but only super-users should be able to modify the max_read_buffer_kb and max_write_buffer_kb files.

-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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